Sessreg
is a simple program for managing utmp/wtmp entries for xdm sessions.

System
V has a better interface to /etc/utmp than BSD; it dynamically allocates
entries in the file, instead of writing them at fixed positions indexed
by position in /etc/ttys.

To manage BSD-style utmp files, sessreg has two
strategies. In conjunction with xdm, the -x option counts the number of
lines in /etc/ttys and then adds to that the number of the line in the
Xservers file which specifies the display. The display name must be specified
as the "line-name" using the -l option. This sum is used as the "slot-number"
in /etc/utmp that this entry will be written at. In the more general case,
the -s option specifies the slot-number directly. If for some strange reason
your system uses a file other that /etc/ttys to manage init, the -t option
can direct sessreg to look elsewhere for a count of terminal sessions.

Conversely,
System V managers will not ever need to use these options (-x, -s and -t).
To make the program easier to document and explain, sessreg accepts the
BSD-specific flags in the System V environment and ignores them.

BSD and
Linux also have a host-name field in the utmp file which doesn't exist in
System V. This option is also ignored by the System V version of sessreg.

This specifies an alternate wtmp file, instead of /usr/adm/wtmp
for BSD or /etc/wtmp for sysV. The special name "none" disables writing
records to /usr/adm/wtmp.

-uutmp-file

This specifies an alternate utmp file,
instead of "/etc/utmp". The special name "none" disables writing records
to /etc/utmp.

-lline-name

This describes the "line" name of the entry. For
terminal sessions, this is the final pathname segment of the terminal device
filename (e.g. ttyd0). For X sessions, it should probably be the local display
name given to the users session (e.g. :0). If none is specified, the terminal
name will be determined with ttyname(3)
and stripped of leading components.

-hhost-name

This is set for BSD hosts to indicate that the session was initiated
from a remote host. In typical xdm usage, this options is not used.

-sslot-number

Each
potential session has a unique slot number in BSD systems, most are identified
by the position of the line-name in the /etc/ttys file. This option overrides
the default position determined with ttyslot(3)
. This option is inappropriate
for use with xdm, the -x option is more useful.

-xXservers-file

As X sessions
are one-per-display, and each display is entered in this file, this options
sets the slot-number to be the number of lines in the ttys-file plus the
index into this file that the line-name is found.

-tttys-file

This specifies
an alternate file which the -x option will use to count the number of terminal
sessions on a host.

-a

This session should be added to utmp/wtmp.

-d

This session
should be deleted from utmp/wtmp. One of -a/-d must be specified.